From the looks of this teardown, the bulk of iPhone's slender innards is the battery. Shown here: "The screen we're pulling away is a somewhat translucent surface, behind it is the touch screen surface itself." Link to "Apple's iPhone Dissected: We did it, so you don't have to," at Anandtech.com.

From the looks of this teardown, the bulk of iPhone's slender innards is the battery. Shown here: "The screen we're pulling away is a somewhat translucent surface, behind it is the touch screen surface itself." Link to "Apple's iPhone Dissected: We did it, so you don't have to," at Anandtech.com.